This is reviving a thread from last summer, but I
recently became interested in the problem:
Damien Doligez <damien.doli...@inria.fr> wrote in
message news:<fa.eok2n4f.141k5pt@ifi.uio.no>...
> Finally, Jacques was not quite right in asserting
that most options
> are short-lived. This is only true if you don't use
"option" in your
> main long-lived data structure. Most seasoned OCaml
programmers know
> it, and sometimes it leads to rather contorted data
structures.
How easy would it be to add an 'optional' keyword for
record types? For example:
type 'a foo = { one : 'a option; mutable two : 'a
option }
would become:
type 'a foo = { optional one : 'a; optional
mutable two : 'a }
Where the latter would unbox the options in the
representation. The
usage would be the same:
let foo = { one = Some 0; two = None }
match foo.one with None -> ... | Some x -> ...
foo.two <- None
foo.two <- Some x
This 'solves' the 'option option' problem by
supporting exactly one level of unboxing for records.
My guess is that this would take care of most of the
long-term data structure needs.
Charles
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